EVOLUTION AND HEREDITY. I4I 



What is your opinion upon the nature of variations ? 

 All my own observation in the field of palaeontology 

 goes to show that they are not fortuitous, but along cer- 

 tain definite lines, as early claimed by Gray and Nageli. 

 Discard the principle of the inherited influences of 

 habit and environment, and you are apparently left 

 without any explanation of this fact. The fortuitous 

 mingling of germ plasms must result in random varia- 

 tions. Granting that they may be of sufficient value to 

 be selected, we still have to eliminate the swamping 

 effect of interbreeding, and the fatal force of the law of 

 regression to race type which, according to Galton, acts 

 even in the offspring of a pair, both of which possess 

 the advantageous variation. 



In addressing this association of the Marine Biologi- 

 cal Laboratory, I chiefly advocate, not so much my own 

 views, as a liberal and generous spirit of discussion, for 

 there is little prospect of a solution of these irreconcilable 

 opinions in the temper which characterizes both sides at 

 present. I claim, if the Lamarckians can demonstrate 

 by palaeontological or other evidence, that acquired 

 characters are inherited, it rests with the embryologists 

 to furnish a theory of physical transmission. On the 

 other hand, embryologists may show conclusively that 

 such inheritance is impossible. In the meantime let us 

 keep in view, without prejudice, all classes of facts which 

 bear upon this most important biological problem. 



